Detection of explosives for security is an area of ongoing global concern. Concerted efforts have been focused on the detection of trace amounts of explosives, including nitrogen-based explosives.
Conventional detection methods, such as X-ray diffraction, nuclear quadruple resonance, ion mobility spectrometry, mass spectrometry, and gas chromatography are known and are highly sensitive and effective. Systems used to carry out these methods, however, are expensive, difficult to maintain, susceptible to false positives, and are not easily manufactured into low-power, portable devices.
Colorimetric techniques are known that can detect the presence of nitrogen-based explosives. Portable colorimetric chemical kits have the value of displaying interpreted optical signals with fast response times. These methods, however, have a number of disadvantages, including low sensitivity, high false alarm rates, and inconvenient analysis and clean-up procedures due to the liquid-based detection mechanisms. In addition, these methods can often expose users to large quantities of chemicals through repeated wet-chemistry style sampling steps.